Grinding in the rear

[Audiobahn77]

I've changed my rear left wheel bearing and its still grinding. Jacked it up and have had it drive and it didn't grind. It comes and goes, but it mostly sounds like it coming from the left side. Any suggestions as what to do now? I really don't think I messed up the new bearing putting that in. (which sucked by the way)

Maybe change the right side bearing?

Any way to see if the brakes are rubbing?

[msrjeep]

you packed the wheel bearing with grease properly? either by hand or using a bearing pack tool.

[Audiobahn77]

these bearings you didn't have to, but yes I loaded them with grease!

[Audiobahn77]

I've noticed it happeneds more when I release the accelerator. When I'd give the Jeep gas it would go away. Hopefully this will help you all troubleshoot it with me. Do you think it would help to bleed the brakes? (hopefully that doesn't sound stupid!)?

[JDPascal]

Sounds to me like the outer pinion bearing. Thats the one under load when coasting.

It is the easiest to check and fix anyway.


The other possibility is gear noise from the ring and pinion on the back (coast) side of the teeth. Not as likely as as the first one but a possibility - especially if the gears have been out before or it has been run with extreemely bad bearing.

I don't think that bleeding the brakes will help this.

JD

[Audiobahn77]

ok, thanks........I'll check that next as soon as someone can tell me exactly where it is located.

97 JGC Laredo I6 4.0L, Dana 35 (I believe)

[JDPascal]

Sorry Audiobahn77, I missed your reply and question.

The outer pinion bearing is at the end of the driveshafts just behind where the yoke or flange is on the differential.

Inorder to inspect it, you will have to remove the pinion seal and install a new one. Check the manual for the torque spec on the pinion nut when it goes back together. It will probably be different for the front and back diffs.

JD

[Audiobahn77]

So I would need a new bearing and a seal. Is there anything else I would need to change it (minus the obvious tools). If you know a good place to order that from online, please post it so I know. I'm in Iceland and parts here are about 6 times the price I can get them online. So far I've found the bearing for $19.79 and a seal for $5.13. There is an installation kit for $62.00. Do you think that it would be better to just go with that? http://www.drivetrain.com/dana35.html


I located in my Chilton's manual that it says to:
-After removing it, install a new seal with a suitable driver.
-STEP 8 //this is the step I'm having troubles understanding// "preload" bearing torque to 1/2 ft. lbs. over the noted release torque as measured above.
-Rotate the pinion gear three or four times with a torque wrench attached to the yoke nut. Measure the amount of torque necessary to rotate the pinion.
-Using a holding tool, tighten the yoke nut in small increments and remeasure until the specified torque is obtained.

If you could explain these a little better in dumb mechanic terms, that would be great. I know what torque wrenches are and how to use them.

[JDPascal]

First of all, if the outside pinion bearing is rough enough to make the noise you describe, you should probably totaly rebearing the dif. That means the two side bearings on the cage and both pinion bearings.

What I would do is pull the diff cover and check the oil and housing for silver bearing material. If you find some, you know what needs to be done. If not, perhaps the bearings aren't flaking off yet and it would be a good idea to pull the pinion yoke and seal to look at the outer bearing.

What the chiltons manual is describing is to check the rotational torque on the pinion with a 0 to 60 inlb torque wrench before you disassemble the yoke.

as an example, If your reading before dissassembly is 12 inlb, the rotational torque on reassembly should be 18 inlb. you might have higher readings than that because of turning the rear axles and wheels and all but thats the idea.

If you are going to rebearing the diff and are ordering parts on line, ORDER ATLEAST 2 EXTRA CRUSH SLEEVES FOR SETTING PINION BEARING PRELOAD WITH THE NEW BEARING. Even experienced mechanics frequently over tighten the bearings on the first try and you cannot reuse the crush sleeve once over torqued.

Crush sleeves from the dealers usually have a price of about $10 - $15 here in Canada. The powertrain suppliers sell them for 75 cents each....

Before you go to any more work on the Diff, have you checked for contact between the exhaust pipe and the frame?? Or eliminated tire noise?? I can't remember if those were mentioned or not.

If you have more questions I check in here a couple of times a day during the holidays.

JD

[Audiobahn77]

What I have done so far....
I have changed the driver's side rear wheel bearing because it sounds like it is coming more from the the left side. I can't quite tell where exactly its coming from. I've jacked it up and spun the rear wheels by hand to see if it was grinding then....it did not, so I put it into gear and gave it some gas and it did not grind. As soon as I put weight on the wheels and drove it, it would grind again. I've changed the fluid in the diff twice now because the first time I was going to change my wheel bearing, I had the wrong parts so I had to put it back together. I haven't noticed anything in the fluid except the second time when I noticed the washer that goes behind one of the gears had slipped out when I was putting back together (from the first time) was grinded up. I didn't have one on hand when I put it back together, so its missing that now, but I don't think that would still cause it to grind. I really don't think the exhaust is doing it because its coming more from the left side and the pipe is on the right. It may be grinding in the middle, I can't really tell though.

[JDPascal]

Ab77

Did the thrust washer go through the drive gears?? If it did, you may have damaged the ring and pinion teeth enough to cause noise.

Also, that thrust washer will change the gear contact in the differential section enough to cause wear inside the cage where the back of the gear sits, especially if there is a limited slip in there.

The debree from the thrust washer grindings would have been circulated directly into the pinion bearings with the oil slung from the ring gear.

I'm sure you don't want to hear this and it's not for sure because I can't inspect the parts but it sounds like a bearing job is needed for sure and maybe a new gear set. Have a close look at the surface where the thrust washer came from behind the little pinion gear inside the cage too. Hope it hasn't done excess damage.

JD

[Audiobahn77]

Well, it did get bent/chewed up a little. I didn't want to use it after it had been messed up. I did not see ANY damage done to the gears and the washer was in one piece. But all this happened after it was already grinding. I need to find an IPB online so I can see where all these bearings are located at. Plus I need to order them too. I'd like to just change the outer pinion bearing first to see if that is all as well as putting a new thrust washer back in. Thanks JDPascal for helping me out!

[Audiobahn77]

DALE! Any input from you on this? I know you're smart about JGCs.

[xj31]

when you changed the axle bearing i assume you reused the axle shaft.thats usually not good because the shaft is actually the inner race of the bearing.in other words if the bearing goes bad,it grinds up the shaft.when you had it apart,how did the shaft look?how about the bearing?if the noise is in fact coming from the left side and it doesnt make noise with no weight on the wheels,then it does sound like its probably the axle bearing.but you also said it happens more when you release the accelerator.that sounds like pinion bearings.I see by your profile that you have a 97 zj.is it a 5.2?the 5.2s came with an aluminum dana 44 that is probably the most failure prone axle known to man.those are notorious for destroying bearings especially carrier bearings.chrysler had a bulletin on those axles to replace them with a reman axle that used to be dirt cheap like $300 or so when they were in warranty.at the shop I work at we used to replace those things literally by the truck load.If you have a 4.0 obviously that doesnt apply.either way it sounds like you need to take everything apart and inspect all the bearings and races.anything that is pitted is obviously bad.sometimes bearings might not look bad but if you spin them by hand and feel any roughness they will probably make noise.by the way JD is giving you some good advice so I hope youre paying attention

[Audiobahn77]

Well, I had my friend drive while I listened and the grinding is coming from the center. The axle was fine and so was the bearing, but I changed the bearing and seal anyways. I think my best bet is the Outer pinnion bearing. My JGC is a 4.0L so it doesn't apply.